When is a war movie not a war movie? When it’s the latest collaboration between Matt Damon and Peter Geengrass (who together respectively starred in and directed the last two Jason Bourne movies), which starts off looking like another Iraq war story but soon turns into something a lot closer to a film noir thriller.

It’s the early weeks of the invasion of Iraq, and Chief Warrant Officer Roy Miller (Damon) and his unit are scouring Baghdad for Weapons of Mass Destruction. Not surprisingly, Miller is getting a little frustrated at dodging snipers only to find the WMD bunker he’s looking for is in fact a disused toilet factory. So when local resident ‘Freddy’ (Khalid Abdalla) turns up at the site of yet another dead-end search and says he saw a bunch of Iraq generals holding a secret meeting in the next suburb over, Miller figures that here’s his big chance to get some real WMD intel straight from the source.

While he gets the intel – but not the general – he also gets in over his head as Pentagon suit Clark Poundstone (Greg Kinnear) and CIA agent Martin Brown (Brendan Gleeson) see his efforts as a chance to push their own agendas.  Brown wants to keep the Iraq army together and use it to stop the country from crumbling into chaos; Poundstone is a neo-con who thinks that democracy will make everything all right. It’s at the stage where Miller sides with Brown (and against history – the Iraq army was disbanded soon after the invasion) that it starts to become clear that, despite the extremely impressive re-creation of Baghdad circa 2003, the story we’re watching is really just an updated version of a gritty detective tale that could have come out of the 1940s.

Miller is the hardboiled hero out to uncover the truth at all costs, the people he thought he could trust are the ones who want the truth covered up, and we know that there’s no happy ending in sight even if he does solve the mystery of the WMDs. Like all good mysteries there’s a lot going on here, but Greengrass keeps all his plates spinning in a way that keeps things from getting too confusing. Unless he wants things confusing, which is usually the case in the numerous gunfights where shaky camerawork, shouted commands and constant motion are the orders of the day.

As seen in the Bourne films, Greengrass knows how to put together exciting action, and while the fights here are more realistic than anything Jason Bourne got up to they retain an edge-of-your-seat energy throughout. There’s a definite view on the Iraq war being expressed here, but it’s hardly controversial to mock George Bush’s “Mission Accomplished” statement, let alone to suggest that things could have been handled better in the wake of the invasion.

Using these events as plot devices in a thriller gives it an energy it couldn’t get from fiction, but it’s a risky move; whether these issues are dead enough for Americans (and the world) to enjoy this consistently gripping thrill-ride remains to be seen.

Green Zone opens in Australian cinemas on Thursday, March 11.
You can view the Green Zone movie trailer here on TheVine.